The present invention relates generally to an improved agricultural round baler, and particularly to improved method and apparatus for wrapping a round bale that prevents stretch film from sticking to the surfaces of the apparatus.
For several years agricultural round balers have been used to consolidate and package crop material so as to facilitate the storage and handling of the crop material for later use. Usually, a mower-conditioner cuts and conditions the crop material for windrow drying in the sun. When the cut crop material is properly dried, a baler, most likely a round baler, is pulled along the windrows to pick up the crop material and form it into cylindrically-shaped round bales. More specifically, the windrow pickup of the baler gathers the cut and windrowed crop material and lifts it into the baling chamber. The baling chamber consists of a pair of opposing sidewalls with a series of belts that rotate and compress the crop material into a cylindrical shape. When the bale has achieved a desired size and density, the operator wraps the bale to ensure that the bale maintains its shape and density. The operator then raises the tailgate of the baler and ejects the bale onto the ground. The tailgate is then closed and the cycle repeated as necessary and desired to manage the field of cut crop material.
The bale wrapping process initially comprised a plurality of wraps of baler twine; however, over the last several years a number of alternatives have been devised. Twine by itself does not wrap the edge of the bale adequately to maintain the shape and density, so one of the alternatives is to use a netting material that is dispensed from rolls with a length slightly longer than width of the round bale. The extra length wraps around the edge of the bale, better holding the package together. Alternatively, a silage wrap material—solid sheet of film, referred to herein as “stretch film”, rather than an open net—is used when it is desired to produce a silage-type feed for livestock. The stretch film is provided in rolls usually slightly longer than the width of the bales being formed, and may or may not include an adhesive on one side (the side intended to be directed toward the bale). It has also been found that both the netwrap and stretch film materials hold and adhere better if they are stretched during the application process.
A troublesome problem presented with mechanisms that apply the stretch film to the bale arises because of its tendency to adhere to smooth surfaces. When the stretch film sticks to the metallic components of the dispensing mechanism, the stretch film has a strong tendency to rip or tear, resulting in miswraps and other material-feeding problems.
The concept of wrapping a round bale with netwrap material, such as shown, for example in U.S. Pat. No. 6,550,218, is not new. Nor is the idea of wrapping a round bale with a thin sheet of plastic material new, such as shown and discussed, for example, in U.S. Pat. No. 4,409,784. However, to date, there has been no commercially viable dispensing mechanism that can successfully handle both netwrap and film wrapping materials.